将矩形对象添加到PDF文件

以下代码片段也适用于Aspose.PDF.Drawing库。

添加矩形对象

Aspose.PDF for .NET支持将图形对象（例如图形、线条、矩形等）添加到PDF文档的功能。您还可以添加矩形对象，并提供用特定颜色填充矩形对象、控制Z-顺序、添加渐变颜色填充等功能。

首先，让我们看看创建矩形对象的可能性。

请按照以下步骤操作：

创建一个新的PDF 文档。
将页面添加到PDF文件的页面集合中。
将文本片段添加到页面实例的段落集合中。
创建图形实例。
为绘图对象设置边框。
创建矩形实例。
将矩形对象添加到图形对象的形状集合中。
将图形对象添加到页面实例的段落集合中。
将文本片段添加到页面实例的段落集合中。
然后保存您的PDF文件。

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void AddRectangle(Aspose.Pdf.Page page, float x, float y, float width, float height, Aspose.Pdf.Color color, int zIndex)
{
    // Create a Graph object with dimensions matching the specified rectangle
    var graph = new Aspose.Pdf.Drawing.Graph(width, height)
    {
        // Prevent the graph from repositioning automatically
        IsChangePosition = false,
        // Set the Left coordinate position for the Graph instance
        Left = x,
        // Set the Top coordinate position for the Graph instance
        Top = y
    };

    // Create a Rectangle object inside the Graph
    var rect = new Aspose.Pdf.Drawing.Rectangle(0, 0, width, height)
    {
        // Set the fill color of the rectangle
        GraphInfo =
        {
            FillColor = color,
            // Set the border color of the rectangle
            Color = color
        }
    };

    // Add the rectangle to the Shapes collection of the Graph
    graph.Shapes.Add(rect);

    // Set the Z-Index for the Graph object to control layering
    graph.ZIndex = zIndex;

    // Add the Graph object to the Paragraphs collection of the page
    page.Paragraphs.Add(graph);
}

创建矩形

创建填充矩形对象

Aspose.PDF for .NET还提供用特定颜色填充矩形对象的功能。

以下代码片段演示如何添加一个用颜色填充的矩形对象。

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void RectangleFilled()
{
    // The path to the documents directory directory
    var dataDir = RunExamples.GetDataDir_AsposePdf_Images();

    // Create PDF document
    using (var document = new Aspose.Pdf.Document())
    {
        // Add page
        var page = document.Pages.Add();

        // Create Graph instance
        var graph = new Aspose.Pdf.Drawing.Graph(100, 400);

        // Add graph object to paragraphs collection of page instance
        page.Paragraphs.Add(graph);

        // Create Rectangle instance with specified dimensions
        var rect = new Aspose.Pdf.Drawing.Rectangle(100, 100, 200, 120)
        {
            // Specify fill color for the Rectangle object
            GraphInfo = 
            { 
                FillColor = Aspose.Pdf.Color.Red 
            }
        };

        // Add rectangle object to shapes collection of Graph object
        graph.Shapes.Add(rect);

        // Save PDF document
        document.Save(dataDir + "CreateFilledRectangle_out.pdf");
    }
}

查看填充纯色的矩形结果：

填充矩形

添加带渐变填充的绘图

Aspose.PDF for .NET支持将图形对象添加到PDF文档，有时需要用渐变颜色填充图形对象。要用渐变颜色填充图形对象，我们需要将setPatterColorSpace设置为渐变轴向阴影对象，如下所示。

以下代码片段演示如何添加一个用渐变颜色填充的矩形对象。

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void CreateFilledRectangleGradientFill()
{
    // The path to the documents directory directory
    var dataDir = RunExamples.GetDataDir_AsposePdf_Images();

    // Create PDF document
    using (var document = new Aspose.Pdf.Document())
    {
        // Add page
        var page = document.Pages.Add();

        // Create Graph instance
        var graph = new Aspose.Pdf.Drawing.Graph(400, 400);

        // Add graph object to paragraphs collection of page instance
        page.Paragraphs.Add(graph);

        // Create Rectangle instance
        var rect = new Aspose.Pdf.Drawing.Rectangle(0, 0, 300, 300);

        // Create a gradient fill color
        var gradientColor = new Aspose.Pdf.Color();
        var gradientSettings = new Aspose.Pdf.Drawing.GradientAxialShading(Aspose.Pdf.Color.Red, Aspose.Pdf.Color.Blue)
        {
            Start = new Aspose.Pdf.Point(0, 0),
            End = new Aspose.Pdf.Point(350, 350)
        };
        gradientColor.PatternColorSpace = gradientSettings;

        // Apply gradient fill color to the rectangle
        rect.GraphInfo.FillColor = gradientColor;

        // Add rectangle object to shapes collection of Graph object
        graph.Shapes.Add(rect);

        // Save PDF document
        document.Save(dataDir + "CreateFilledRectangleGradient_out.pdf");
    }
}

渐变矩形

创建带Alpha颜色通道的矩形

Aspose.PDF for .NET支持用特定颜色填充矩形对象。矩形对象还可以具有Alpha颜色通道，以提供透明外观。以下代码片段演示如何添加一个带Alpha颜色通道的矩形对象。

图像的像素可以存储有关其不透明度的信息以及颜色值。这允许创建具有透明或半透明区域的图像。

与其使颜色透明，不如每个像素存储有关其不透明程度的信息。此不透明度数据称为alpha通道，通常存储在像素的颜色通道之后。

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void RectangleFilled_AlphaChannel()
{
    // The path to the documents directory directory
    var dataDir = RunExamples.GetDataDir_AsposePdf_Images();

    // Create PDF document
    using (var document = new Aspose.Pdf.Document())
    {
        // Add page
        var page = document.Pages.Add();

        // Create Graph instance
        var graph = new Aspose.Pdf.Drawing.Graph(100, 400);

        // Add graph object to paragraphs collection of page instance
        page.Paragraphs.Add(graph);

        // Create first rectangle with alpha channel fill color
        var rect = new Aspose.Pdf.Drawing.Rectangle(100, 100, 200, 120)
        {
            GraphInfo = 
            { 
                FillColor = Aspose.Pdf.Color.FromArgb(128, 244, 180, 0) 
            }
        };

        // Add the first rectangle to the shapes collection of the Graph object
        graph.Shapes.Add(rect);

        // Create second rectangle with different alpha channel fill color
        var rect1 = new Aspose.Pdf.Drawing.Rectangle(200, 150, 200, 100)
        {
            GraphInfo = 
            { 
                FillColor = Aspose.Pdf.Color.FromArgb(160, 120, 0, 120) 
            }
        };

        // Add the second rectangle to the shapes collection of the Graph object
        graph.Shapes.Add(rect1);

        // Save PDF document
        document.Save(dataDir + "CreateFilledRectangle_out.pdf");
    }
}

矩形Alpha通道颜色

控制矩形的Z-顺序

Aspose.PDF for .NET支持将图形对象（例如图形、线条、矩形等）添加到PDF文档的功能。当在PDF文件中添加多个相同对象的实例时，我们可以通过指定Z-顺序来控制它们的渲染。Z-顺序在我们需要将对象重叠渲染时也会使用。

以下代码片段演示了在彼此之上渲染矩形对象的步骤。

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void AddRectangleZOrder()
{
    // The path to the documents directory directory
    var dataDir = RunExamples.GetDataDir_AsposePdf_Images();

    // Create PDF document
    using (var document = new Aspose.Pdf.Document())
    {
        // Add page
        var page = document.Pages.Add();

        // Set size of PDF page
        page.SetPageSize(375, 300);

        // Set left and top margins for the page object as 0
        page.PageInfo.Margin.Left = 0;
        page.PageInfo.Margin.Top = 0;

        // Create rectangles with different colors and Z-Order values
        AddRectangle(page, 50, 40, 60, 40, Aspose.Pdf.Color.Red, 2);
        AddRectangle(page, 20, 20, 30, 30, Aspose.Pdf.Color.Blue, 1);
        AddRectangle(page, 40, 40, 60, 30, Aspose.Pdf.Color.Green, 0);

        // Save PDF document
        document.Save(dataDir + "ControlRectangleZOrder_out.pdf");
    }
}

控制Z顺序

将线对象添加到PDF文件将椭圆对象添加到PDF文件